This invention generally relates to feedstocks for domesticated ruminants. More specifically, this invention relates to the production of cow milk in an increased volume and/or with an enhanced fat content.
Ruminant feeds generally depend on readily fermentable carbohydrates and chopped ensiled forages. This type of feed generates acids in the rumen which are not completely counterbalanced by dietary or endogenous bases and buffers. Under elevated acidic conditions, the population of fiber-digesting rumen microorganisms is less prolific than a population present under more alkaline conditions. When the pH in the rumen tends toward neutral, a lactating ruminant can utilize the higher volatile fatty acid production by the microorganisms to increase the fat content of the milk yield.
It is known that sodium bicarbonate and/or magnesium oxide are effective for increasing the milk and/or milk fat production of ruminants fed high acid-producing diets [J. Dairy Sci., 65, 712 (1982)]. However, these additives can have the undesirable effects of reducing feed intake and decreasing the serum levels of potassium and magnesium.
In another aspect, this invention is concerned with the dietary nitrogen required to support rumen microbial growth, and to satisfy metabolic requirements for protein synthesis. The concentration of rumen ammonia necessary for optimal microbial growth and rumen fermentation in cattle is estimated at about 200 milligrams per liter of rumen fluid. The addition of a source of non-protein nitrogen (NPN) to the diet is beneficial in achieving a favorable equilibrium level of rumen-generated ammonia.
Ruminal bacteria strains such as Streptococcus bovis and Bacteroides succinogenes are described in J. Bacteriol., 84, 605 (1962).
Publications relating to NPN in feed rations for ruminants include U.S. Pat. Nos. 2,560,830; 2,687,354; 2,748,001; 2,840,473; 2,853,385; 2,861,886; 2,965,488; 3,180,735; 3,259,501; 3,416,928; 3,512,986; 3,523,798; 3,551,162; 3,576,642; 3,600,188; 3,635,725; 3,642,489; 3,653,909; 3,677,767; 3,684,518; 3,733,203; 3,852,498; 3,873,728; 3,873,733; 3,937,846; 3,988,483; 4,027,043; 4,044,156; 4,089,980; 4,186,213; 4,194,012; 4,232,046; 4,376,790; 5,733,590; and the like, incorporated by reference.
Ruminants have the unique ability to convert NPN to animal protein. The microbial flora in the rumen degrade NPN to ammonia, which is then converted to protein. The most widely used NPN source in ruminant feed is urea. However, there are major problems associated with the use of urea in ruminant feed. Enzymatic breakdown of urea to ammonia often occurs faster than the microbial uptake of the liberated ammonia. The excess ammonia thus produced can reach toxic levels in the ruminant, and may lead to severe disability. Much of the excess ammonia is absorbed in the animal's bloodstream, and then is converted back to urea in the liver and excreted. The lost ammonia is not utilized for protein synthesis, which results in a less efficient utilization of available nitrogen.
A broad range of research has been directed to means for controlling the rate of NPN fermentation in the rumen, and the resultant equilibrium level of ammonia in the rumen. A NPN source such as urea typically has been physically blended with various saccharides such as starch or molasses, or chemically bound to saccharides, to produce slow-release NPN formulations which do not have a satisfactory combination of properties for purposes of ruminant nutrition and productivity. The release rate is too high for the physically blended NPN, and too slow for the chemically bound NPN.
There is continuing interest in the development of new and improved feedstocks and methods for efficient ruminant management, and the provision of value-added meat and dairy products.
Accordingly, it is an object of the invention to provide an improved NPN feedstock supplement for enhanced rumen health and increased microbial population in ruminants.
It is another object of this invention to provide a ruminant feedstock which has a content of improved NPN supplement.
It is another object of this invention to provide a method for increasing the milk production of dairy cattle.
It is another object of this invention to provide a method for enhancing the fat content of cattle milk production.
It is a further object of this invention to provide a method for increasing the efficiency of feedstock utilization by ruminants, and for decreasing the relative volume of manure accumulation.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.
Of related interest with respect to the present invention, are publications which include J. Anim. Sci., 67, 820 (1989), and U.S. Pat. Nos. 3,413,118; 3,843,799; 4,118,513; 4,196,194; 4,857,332; and 5,803,946; incorporated by reference.